UPDATE 1-Roche's Avastin helps slow ovarian cancer progression

* Second study backs up earlier late-stage trial

* Roche stock up 0.7 pct, outperforms sector index

(Adds details, background, analyst comment, share price)

ZURICH, July 2 (Reuters) - Roche Holding AG's ROG.VX cancer drug Avastin, in combination with chemotherapy, helps women with ovarian cancer live for longer without their disease worsening, a second late-stage study has shown.

The results come after another Phase III trial showed using Avastin with chemotherapy, followed by continued use of the drug, also improved progression-free survival.

“This second trial in ovarian cancer confirms the efficacy of Avastin for the treatment of ovarian cancer. No details were given yet as the data will be presented at an upcoming scientific conference, likely ESMO in September,” Vontobel analyst Andrew Weiss said.

“We carry 1 billion Swiss francs ($942.5 million) of peak sales expectations for this indication in our Avastin expectations,” he said.

At 0831 GMT, stock in the group was trading 0.7 percent firmer, while the European healthcare index .SXDP was down 0.4 percent.

The second trial used a lower dose of Avastin and analysts said it will be interesting to see how the efficiency of this compares with the higher dose.

Avastin, which starves tumours of blood supply, is the first targeted therapy to show a benefit in ovarian cancer, one of the most deadly types of the disease.

Avastin, which is Roche’s top-selling drug, is already a key weapon in the fight against colon, lung, breast and other types of cancers, but it has stumbled at key hurdles this year, failing in late-stage stomach and prostate cancer studies.

The drug is set to be the world’s biggest selling prescription medicine, with annual sales of some $9 billion a year, according to consensus forecasts.

Also on Friday, Britain’s health cost watchdog, the National Institute for Health and Clinical Excellence (NICE), said on Friday it was recommending Roche’s arthritis drug RoActemra be paid for on the taxpayer-funded National Health Service (NHS). [ID:nLDE6601L3] (Reporting by Katie Reid; Editing by Mike Nesbit) ($1=1.061 Swiss francs)